1. Field of the Invention
The present invention relates to the field of flyback transformers, and more particularly, to a flyback transformer having an improved low voltage bobbin that is capable of installing at least two different sizes of iron shafts. The improved low voltage bobbin according to this invention can prevent short-circuiting while installing different sizes of iron shafts.
2. Description of the Prior Art
A flyback transformer is generally implemented within the circuits of a display device for providing distinctive voltages required by the circuit operation of the display device. Due to the trend toward smaller or thinner customer electrical apparatuses, the dimension of the flyback transformer is limited.
Please refer to FIG. 1. FIG. 1 is a perspective diagram of a conventional low voltage bobbin of a flyback transformer (FBT). The low voltage bobbin generally comprises a base portion 1 and a core portion 2 that is pivotally connected to a front side of the base portion 1. Multiple insertion pins 13 extend upwardly from the outer wall 11 of the half-moon-like base portion 1. Wire winding rods 14, which extend axially from back side of each of the insertion pins, are provided.
Please refer to FIG. 2 and FIG. 3 with respect to FIG. 1. FIG. 2 is a cross sectional view of a prior art low voltage bobbin with an iron shaft installed therein. FIG. 3 is a plane view of the low voltage bobbin of FIG. 2. As shown in FIG. 2 and FIG. 3, an iron shaft 3 is inserted into the space defined by the core portion 2 and the base portion 1. The surface of the iron shaft 3 is in contact with the inner wall 12 of the base portion 1.
However, the prior art low voltage bobbin is only suitable for a specific size of iron shaft, for example, 10 mm iron shaft. When one wants to install a bigger iron shaft into the low voltage bobbin, for example, 11 mm iron shaft, he or she must order a bigger low voltage bobbin in order to fit the bigger iron shaft, and also a bigger casing that covers the low/high voltage bobbins. This will largely increase the overall production cost. Moreover, the bigger low voltage bobbin obeys the current trend of size shrinking.
FIG. 2 and FIG. 3 also imply the difficulties and problems that might be encountered when installing a 11 mm iron shaft into a 10 mm low voltage bobbin. As shown, the gap between the wire winding rods 14 and the outer wall 11 of the base portion 1 is narrow. Without changing the size of the low voltage bobbin, the installation of a 11 mm iron shaft into the 10 mm low voltage bobbin will cause short-circuiting problems resulting from undesirable contact between the wire winding rods 14 and the outer wall 11.
Consequently, there is a need to provide an improved low voltage bobbin of a flyback transformer to solve the above-mentioned problems.
It is therefore a primary object of the present invention to provide an improved low voltage bobbin of a flyback transformer that is capable of installing at least two different sizes (ex. 10 mm and 11 mm) of iron shafts and also maintaining the insulation property and original size of the low voltage bobbin.
It is another objective of this invention to provide an improved low voltage bobbin for flyback transformers having mechanically strengthened slender wire winding rods.
According to the claimed invention, the low voltage bobbin comprises a core portion, a base portion, a plurality of insertion pins formed on an outer wall of the base portion, and a wire winding rod axially extending from each of the insertion pin. The thickness of portion of the outer wall of the base portion that is corresponding to each of the plurality of insertion pins is thinned down. Each of the wire winding rod has a descending diameter from a root end to a free distal end of the wire winding rod.
Moreover, symmetric cutting sides may be formed on each of the elliptic rods on opposite ends of the long radius.
Further, symmetric cutting sides may be formed on two sides of each of the elliptic rods.
It is to be understood that both the forgoing general description and the following detailed description are exemplary, and are intended to provide further explanation of the invention as claimed. Other advantages and features of the invention will be apparent from the following description, drawings and claims.